Tuesday, February 23, 2010

It's not related to pest control, but for anyone interested in the science side of entomology, the plight of the monarch butterfly is making headlines in the insect science community. Overwintering monarch butterflies are having a tough winter in the Sierra Chincua mountains, in the Monarch Butterfly Biosphere Reserve in Mexico. Record torrential rains (which have been devastating for people in the region as well) along with cold temperatures have not been kind to monarchs this winter.

If you are not familiar, nearly all monarch butterflies, Danaus plexippus, in eastern North America migrate each fall to the Sierra Chincua mountains to spend the winter in a site that has ideal overwintering conditions for butterfly survival. In one of the true migratory wonders of nature, each year these butterflies start a return trip north to recolonize areas with milkweed plants and build up their population numbers.

Monarch Watch is a non-profit group dedicated to Monarch Conservation. In the blog postings at Monarch Watch, observers have been following the weather in central Mexico closely. Reports so far are fragmentary but of concern to monarch watchers. According to a recent email sent by Chip Taylor of Monarch Watch, surviving monarchs may be down more than 90% following the storms. Researchers fear that it will take monarchs at least two, and perhaps more, years to recover from the effects of this year's winter weather.

Of course monarchs have survived bad weather for hundreds, thousands, perhaps tens of thousands of years. What makes bad weather significant today is that monarch refuges are shrinking due to habitat loss caused by illegal forestry and development in the key butterfly preserves. With the loss of each hectare of prime butterfly habitat the monarch's survival becomes a little more tenuous.

No one knows the monarch's ultimate fate, but by all accounts we will see far fewer monarchs on the wing this year.

Monday, February 22, 2010

One of the most unusual, and intriguing structural pests we see commonly in north Texas is the cricket hunting wasp, Liris sp. A member of the solitary wasp family, Sphecidae, these black wasps with dusky wings range in size from 10-20 mm (3/8-3/4 inch). They can mysteriously appear indoors nearly any time of year, but February is a common month of emergence, for reasons not fully understood.

Cricket hunting wasps really have no food interest in homes per se, but their natural behavior and nesting preferences often entice them to enter structures and accidentally become pests.

Adult wasps spend much of their outdoor time searching for crickets, which they attempt to sting, capture, and transport live to a nest--typically described as an abandoned rodent burrow or other similar natural cavity in the ground. After a cricket has been subdued and carried to the nest, the female lays on it a single egg. After hatching, the larva begins feeding immediately on its paralyzed cricket prey. One cricket probably provides enough food for a single wasp to develop.

So far so good. In their basic biology, the cricket hunter wasps are similar to other solitary wasps, such as cicada killer wasps. They are simply one of hundreds of species of beneficial insects that help to keep potential pest populations down. Unfortunately, cricker hunter wasps become pests when instead of using an outdoor rodent burrow, they nest under the concrete slabs of homes and buildings, or through openings or weep holes in exterior walls.

The adults that appear indoors are not the same individuals that carefully tuck crickets into the wall voids and under foundations. The wasps appearing indoors represent the offspring of summer- and fall-active adults. Dozens or even hundreds of paralyzed crickets may be placed in walls or under the slabs of buildings during the warm season leading up to fall. Each of these crickets with eggs may eventually produce wasps that emerge under or inside the house. Apparently many of these 2nd generation wasps find their way into indoor living areas instead of making their ways back outside where the crickets are. Wasps that appear in the dead of winter may either misjudge emergence times because of the warm shelter in which they are placed, or else their emergence may be stimulated by the fluctuating cold and warm temperatures so common this time of year.

Control of cricket hunting wasps can be difficult. Wall voids or bath trap areas may be treated with aerosol pyrethrins or residual insecticides; but the only effective solution in most cases may simply be the vacuum or fly swatter. Your customer should be assured that emerging wasps are not aggressive and are unlikely to sting. The best approach for cricket wasp problems is prevention. To reduce the risk of continual use of the structure as a nesting site for cricket hunters, try screening weep holes in brick veneer, filling holes leading under foundations, and careful sealing around baseboards, bathtubs and toilet. Outdoor application of residual granular insecticides, such as fipronil or pyrethroid insecticides, may provide some additional control. Such treatments should be made in a 1-2 foot band around the foundation of areas in the home where wasps are active. Look for areas of sandy soil, or soil subsidence, especially on south-facing walls. For more information about cricket hunter wasps and their control, see http://citybugs.tamu.edu/factsheets/household/misc-house/ent-2009/

There is much we still don't know about this insect, especially areas of the country where it is recorded as a pest. If you encounter accounts with these wasps, especially outside the Dallas area or during spring, summer or fall months, please let me know via email or a comment on this blog.

Tuesday, February 16, 2010

A new study out today by Changlu Wang and colleagues at Rutgers and Purdue University had so many interesting findings, I just have to share them with you. Wang and colleagues investigated characteristics of the bed bug infestation and dispersal in a 223-unit high-rise apartment building in Indianapolis, Indiana between December 2008 and April 2009. They used bed bug interceptors, which I've reviewed here before, visual inspections and resident interviews to learn about how bed bugs travel through high density, high-rise apartments.

A few of the observations coming out of this study:

In this study, conventional (pesticide-based) pest control monthly treatments for bed bugs was mostly ineffective, though the approach used by the contractor was not explicitly described in this paper.

45% of the 223 high rise apartment units experienced documented bed bug infestations within 3+ years of the initial reported infestation, showing how fast a bed bug infestation can spread in multi-floor housing.

Adult bedbugs were 9 times more likely to disperse out an apartment doorway than nymphs. Although migration through apartment walls was not monitored, the authors noted that there was no reason to assume that dispersal behavior would be different via that route.

53% of infested apartments were adjacent to another infested apartment, suggesting that direct apartment-to-apartment dispersal is likely, either through walls or hallways. Surprisingly to me, hallways appeared to be a relatively common highway for dispersal. The researchers noted an average of six bed bug immigrants leaving infested apartments via the front door per month. How many of these actually survived to make it to a neighboring apartment was not determined.

I think one of the most interesting and significant findings was that 50% of the interviewed residents who had infestations were unaware of the bed bugs in their apartments. Many people, apparently, either show no reaction to bed bug bites, or attribute the welts to some other cause. This could explain how bed bug infestations can develop before being noted or reported.

The Climbup® Insect Interceptor proved to be a useful tool for monitoring bed bugs, even in rooms with relatively low bed bug populations. Significantly, the study also mentions use of the monitors with a new bed bug-attractant lure manufactured by Bedoukian Research Inc., a manufacturer of flavor and fragrance chemicals in Danbury, Connecticut. Wang et al. report that in their unpublished laboratory studies the lure was effective at attracting bed bugs from a 30 cm (1 foot) distance. Although there are several lures that may be effective at attracting bed bugs from longer distances, an effective solid lure with slow release technology would be a real breakthrough for the bed bug control industry. According to Izzy Heller, Sales Manager at Bedoukian, commercial availability of their product is at least a year away, as they continue to collect data and explore EPA registration. Keep posted.

Interceptors in the study were used under bed posts and next to entry doors of study apartments. These interceptors appeared to provide some control of bed bugs in addition to providing residents with peace of mind during the extermination period.

I came away with two take-home messages from this paper. First, any protocol for treating bed bugs in apartments or hotels should, at a minimum, include inspection of adjacent units, regardless of whether the resident has seen bed bugs. Second, if you are in the bed bug business, or the apartment management business, the Climbup® Interceptor is a nifty, low cost tool for assessment and possibly, to some extent, control.

While the topic of phorid flies is hot off the press here at Insects in the City, I thought I'd pass on some great photos by John Abbott at the University of Texas. John has become proficient with his high speed strobe flash and has taken some amazing pictures.

Lately John has focused his big camera lens on phorid flies. Now these are not the same phorid flies I discussed yesterday in this blog. These are exotic species of flies, in the insect family Phoridae, that have been recently released in the U.S. to help manage imported fire ants, Solenopsis invicta. These insects reproduce by laying an egg in the neck of a fire ant. The egg hatches and the larva migrates through the body of the fire ant, eventually ending up in the head capsule, where it pupates. During the last phase of the migration the fire ant worker dies and it's head falls off. You may have heard these flies referred to in the press (anything in Texas that kills fire ants ends up in the press) as the decapitating phorid fly. Actually there are several species, some of which have successfully established in portions of Texas.

The bad news is that so far phorid fly researchers have not been able to document any significant decline in fire ant numbers where these flies have been established. That shouldn't dim the satisfaction we get from knowing that for at least some fire ants we are paying back misery for misery.

Monday, February 15, 2010

Like most readers of this blog, I get a number of insect specimens for identification each week. Today's specimen was a phorid fly, and it came in typical condition. Flatter than an armadillo on the Interstate.

Doing this kind of work requires you to know your insects and key characters well. You and I know many kinds of insects by sight although we might have a hard time telling you how we know it, or describing the species to someone else. "It just looks like one!" Unfortunately, that's really not good enough though for what we do in a lot of pest control.

Take today's phorid fly. All the specimens I received today came in flat, but at least one of the specimens was pressed neatly enough to reveal two key characters.

Phorid flies are relatively easy to identify by their size and hump-backed appearance. This is probably how most PMPs would ID this critter. But with a flattened specimen like this, the humpbacked appearance is not conclusive. Two other characters come to the rescue.

In addition to size and shape, two other characters are "diagnostic" (biology talk meaning that they clinch the identification). All phorid flies have enlarged hind femurs and distinctive wing veination. A closer look at the sample shows the big, flattened femurs (the first easily visible leg segment coming off the body) and that special phorid fly wing veination. Phorid flies have a unique trio of heavy veins in the front wings. I think they come together looking a little like a pocketknife blade (see bottom picture). Once you see those two characters, you can be sure at least that you're looking at a fly in the phorid family.

Almost every insect we deal with in pest control has diagnostic characteristics that distinguish it from other, similar species. These are not always easily seen on every specimen, however. This is one of the reasons why you should always send an identifier as many specimens as you can collect. A half-dozen to a dozen is usually good, but the more the merrier.

Phorid flies are interesting critters. They most commonly show up in ground level floors of buildings. One of the most common causes of heavy infestations is a broken sewer line. When sewage leaks from an underground line it mixed with the surrounding soil and creates a perfect habitat for phorid fly breeding. How would flies get deep underground to lay eggs in the first place? That's one of the remarkable things about this insect. It has the uncanny ability to follow the smallest cracks and crevices, even deep underground, following the yummy smells of decomposition. One of its other names is "coffin fly" for its ability to insinuate its way into caskets stored in mausoleums and even, supposedly, deeply buried graves. Other breeding sites include animal carcasses, dead insects (in moist situations), manure, fungi and decaying plant material. As with all indoor fly problems one must get to the source to achieve control. No matter what dark and scary places your search takes you.

Friday, February 12, 2010

Does your company work in public housing? If so, you know the overwhelming challenge of being in charge of protecting hundreds of low-income families from cockroaches, rodents and bed bugs. It's not an easy job, and generally not one of the better paying gigs either. But it's hard to think of a better place to make a difference in people's quality of life.

This week I traveled to Houston, TX to conduct a training with staff and residents at Lyerly, a public housing facility for the elderly. I was privileged to be able to do the training with Nancy Crider of the UT Center for Public Health, Roselia Guerrero of the Houston Health Department and Steve Toth of the Southern Region IPM Center in North Carolina. The folks we trained were great, and despite some initial skepticism most seemed to enjoy learning about pests and IPM. One of the nicest things about the training was having PMP Jesse Longoria and some of his employees from Apple Pest Control, Lyerly's pest management provider, sit in on most of the day-long class. It was an excellent way to get PMP, management and residents on the same page with their pest control program. I'm hoping we did some good.

I am especially hopeful because I believe that education is one of the most important, if underused, tactics in the PMP's toolkit. You should have seen the wide eyes when we peeled back the gasket on a refrigerator door in a clean, unoccupied apartment, to reveal the dozens of nymphal German cockroaches waiting patiently for the next tenant to move in. For the maintenance staff and the residents it was a teachable moment. They learned how important it is to clean and treat around all potential harborages, and what is meant by a crack and crevice. I'm pretty sure the residents we taught this week have a better understanding of the importance of pest control and their roles in the IPM process.

There's a wonderful new video training resource for any pest control company who works in multifamily housing (It should be especially helpful for public housing accounts, where resident education is often a mandatory part of their tenant agreement). It's available free, online at the website for the Northeastern IPM Center's website for IPM in public housing. Written by Allison Taisey at Cornell University, the video is called The Tenant's Role in IPM. It's about 15 minutes long and includes actors posing as housing manager and tenant. Together they learn about cockroaches and bed bugs, and the tenant's role in IPM.

The resident's information page also has several good fact sheets on pests common in public housing that you can download and give to residents or management at housing facilities and apartments. The video makes a great discussion starter to kick-start a training session with any of your multifamily housing clients.

The next time you head out to your public housing account, don't forget to wear your educator's hat. It could make a big difference in your effectiveness as a PMP.

Friday, February 5, 2010

I think most pest control professionals with kids eventually get asked to give a talk at a child's school, help with an insect collection, a merit badge or a 4-H project. Have we got a resource for you! It's a web site designed for 4-H kids, but I think it might help you look like the "bug champion" for your 6th grader's science project. My colleague Pat Porter and friends from the Texas A&M entomology department have also put together a great video library with tips on how to collect and preserve insects.

Tuesday, February 2, 2010

A sample came through my office today of what I diagnosed as a dark-eyed fruit fly. PMPs report that this larger cousin of the red-eyed fruit fly is becoming more common in commercial kitchen accounts.

There are multiple species of what may be called dark-eyed fruit flies, but unfortunately no good online taxonomic keys geared toward the pest control industry. Names of dark-eyed fruit flies that one hears bandied about include Drosophila repleta, D. hydei, and D. robusta.

Fruit flies are generally smaller than phorid flies, but the dark-eyed variety is about the same size as a phorid and more likely to be confused with this pest. Phorid flies are hump-backed in appearance with wide femurs (segment next to body) on the hind pair of legs. The slender arista (final antennal segment) of the fruit fly is feathery (plumose) in the fruit fly and is not in the phorid fly.

I have no idea what species I have in hand, but there does seem to be a significant difference in breeding sites between the common red-eyed fruit flies (Drosophila melanogaster and D. simulans) and these so-called dark-eyed fruit flies.

According to Gerry Wegner, with Varment Guard Environmental Services in Ohio, dark-eyed fruit fly species occur more frequently in and around floor drains, under cracked or broken floor tiles, under and around cove tiles at wall edges, and sometimes in the dirty feet of kitchen equipment.

According to Eric Smith, with Dodson Pest Control in Lynchburg, Virginia, the different species of dark-eyed fruit flies appear to be similar from a pest control perspective. Dark-eyed species tend to be more visible because of their larger size and their behavior of resting out on walls and vertical surfaces. They also breed in more highly deteriorated organic matter than their smaller cousins. Bacterial drain cleaners (such as Smith's favorite: Invite Biofoam) applied to drains repeatedly will clean up the organic matter that these flies feed on. Dodson technicians are generally successful with three foam applications per month in tough accounts.

A Google search brought me to a post on a chat site for Drosophila enthusiasts at bio.net. There, Drosophila researcher Hampton Carson, University of Hawaii at Manoa, noted that repleta has some distinct biological preferences for breeding sites. He recommends that PMPs include rest-rooms, and particularly urinals, in their IPM inspections. Some of repleta's relatives (e.g., D. mercatorum) are carrion feeders. At least two species, D. repleta and D. robusta, are sometimes pests of poultry houses and attracted to manure. According to Wegner, this might explain the reported success of moist cat food as an attractant for some of the dark-eyes species.

Dark-eyed fruit flies may be a little tougher to control than regular fruit fly infestations. This makes it important to diagnose these flies properly, especially in health-related accounts such as nursing homes and hospitals.

I spoke today for the first time with Ben Hottel, a Master's student at the University of Illinois, who is interested in devoting his research to fruit flies associated with structural pest control. I promised to help Ben in whatever way I can with his research. Perhaps more about this in a later blog, because I suspect Ben will be seeking fruit fly specimens for his survey over the next year or two.

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About Me

I have served as entomology specialist for Texas AgriLife Extension since 1989. I get to work with, and for, a bunch of great people including pest management professionals, school facilities managers, extension volunteers, researchers and other extension professionals. My areas of specialty center on research on insects affecting man including spiders, scorpions, fire ants, termites and others. My program also focuses on training school maintenance professionals in principles of integrated pest management (IPM). Our goal is to make schools healthier, cleaner places to study and live.